• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.71-77
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• 2011

Main parameters of the screen printing were determined and the printing parameters were optimized for 0402, 0603, and 1005 chips in this study. The solder pastes used in this study were Sn-3.0Ag-0.5Cu and Sn-0.7Cu. The process parameters were stencil thickness, squeegee angle, printing speed, stencil separating speed and gap between stencil and PCB. The printing pressure was fixed at 2 $kgf/cm^2$. From ANOVA results, the stencil thickness and the squeegee angle were determined to be main parameters for the printing efficiency. The printing efficiency was optimized with varying two main parameters, the stencil thickness and the squeegee angle. The printing efficiency increased as the squeegee angle was lowered under 45o for all chips. For the 0402 and the 0603 chips, the printing efficiency increased as the stencil thickness decreased. On the other hand, for the 1005 chip, the printing efficiency increased as the stencil thickness increased.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.293-298
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• 2011

The most widely used method to form an electrode in industrial solar cells are screen printing. Screen printing is characterized by a relatively simple and well-known production sequence with high throughput rates. However the method is difficult to implement a fine line width of high-efficiency solar cells can not be made. The open circuit voltage(Voc) and the short circuit current density(Jsc) and fill factor(FF) need to be further improved to increase the efficiency of silicon solar cells. In this study, gravure offset printing method using the multicrystalline-silicon solar cells were fabricated. Gravure off-set printing method which can print the fine line width of finger electrode can have the ability reduce the shaded area and increase the Jsc. Moreover it can make a high aspect ratio thereby series resistance is reduced and FF is increased. Approximately $50{\mu}m$ line width with $35{\mu}m$ height was achieved. The efficiency of gravure off set was 0.7% higher compare to that of scree printing method.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.126-126
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• 2012

In past decades, the themal inkjet (TIJ) printer has been widely used as one of the most well-known digital printing technology due to its low cost, and high printing quality. Since the printing speed of TIJ printers are much slower than that of laser printers, however, there has been intensive efforts to raise the printing speed of TIJ printers. One of the most plausible methods to raise the printing speed of TIJ printers is to adopt a page-wide array TIJ printhead. To accomplish this goal, the high efficiency inkjet heating resistor films should be developed to settle the high power consumption problem of a page-wide array TIJ printhead. In this study, we investigated noble metal based multicomponent thin film resistor films prepared by atomic layer deposition (ALD) for a high efficiency inkjet printhead. Design concept, preparation, material properties of noble metal based multicomponent thin films will be discussed in terms of mutlfunctionality.

• Current Photovoltaic Research
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• v.10 no.3
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• pp.90-94
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• 2022

The screen-printing method is the most mature solar cell fabrication technology, which has the advantage of being faster and simpler process than other printing technology. A front metallization printed through screen printing influences the efficiency and manufacturing cost of solar cell. Recent technology development of crystalline silicon solar cell is proceeding to reduce the manufacturing cost while improving the efficiency. Therefore, screen printing requires process development to reduce a line width of an electrode and decrease shading area. In this paper, we will discuss the development trend and prospects of screen-printing metallization using metal paste, which is currently used in manufacturing commercial crystalline silicon solar cells.

• Fashion & Textile Research Journal
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• v.24 no.5
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• pp.505-518
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• 2022

3D printing technology, also known as additive manufacturing(AM), has not been actively used in the clothing industry despite its potential for economic, environmental, and labor efficiency. Therefore, this study aims to propose a new 3D printing method for the clothing industry, which will be more readily accessible. This roll-type printing method can print wide-sized patterns at once using a 3D modeling program and a FDM 3D printer and help overcome the limitations imposed by the size of the printer. Then, to demonstrate the practical application cases of this printing method, bags of three designs were developed. Prior to product development, a thickness test was performed for stable printing using TPU(Thermoplastic Poly Urethane) filament, and a thickness of 0.45 mm was found to be most suitable for it. Next, the time efficiency test showed that the roll-type printing method takes less time compared to the general printing method in printing wide-sized patterns. Based on these tests, three bags, , and , were developed to confirm the suitability of the roll-type printing method for product development. The advantages of 3D roll-type printing can lie in overcoming of the spatial limitation, and the environmental sustainability as it can reduce waste from the production process. This study is significant in that it presents a new 3D printing method to improve the space limitations and time inefficiency of 3D printers.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.171-171
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• 2012

In this study, we fabricated the high-brightness AlGaInP-based red light emitting diodes (LED)s using by direct printing technique and inductive coupled plasma (ICP) reactive ion etching (RIE). In general, surface roughening was fabricated by wet etching process to improve the light extraction efficiency of AlGaInP-based red LED. However, a structure of the surface roughening, which was fabricated by wet etching, was tiled cone-shape after wet etching process due to crystal structure of AlGaInP materials, which was used as top-layer of red LED. This tilted cone-shape of surface roughening can improve the light extraction of LED, but it caused a loss of the light extraction efficiency of LED. So, in this study, we fabricated perfectly cone shaped pattern using direct printing and dry etching process to maximize the light extraction efficiency of LED. Both submicron pattern and micron pattern was formed on the surface of red LED to compare the enhancement effect of light extraction efficiency of LEDs according to the diameter of sapphire patterns.After patterning process using direct printing and ICP-RIE proceeded on the red LED, light output was enhanced up to 10 % than that of red LED with wet etched structure. This enhancement of light extraction of red LED was maintained after packaging process. And as a result of analyze of current-voltage characteristic, there is no electrical degradation of LED.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.1015-1020
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• 2012

Resistance of the front electrode is the highest proportion of the ingredients of the series resistance in crystalline silicon solar cell. While resistance of the front electrode is decreased with larger area, it induces the optical loss, causing the conversion efficiency drop. Therefore the front electrode with high aspect ratio increasing its height and decreasing is necessary for high-efficiency solar cell in considering shadowing loss and resistance of front electrode. In this paper, we used the screen printing method to form high aspect ratio electrode by multiple printing. Screen printing is the straightforward technology to establish the electrodes in silicon solar cell fabrication. The several printed front electrodes with Ag paste on silicon wafer showed the significantly increased height and slightly widen finger. As a result, the resistance of the front electrode was decreased with multiple printing even if it slightly increased the shadowing loss. We showed the improved electrical characteristics for c-Si solar cell with repeatedly printed front electrode by 0.5%. It lays a foundation for high efficiency solar cell with high aspect ratio electrode using screen printing.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.115-122
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• 1997

The field of printing use to pressurization ink using screen gassamer that is called screen printing. Existing cleaning solvent using screen printing are the organic solvents including aromatic compounds carried with poisonous and stench. Besides, cleaning method of current screen printing are for the most part mixed cleaning method of dipping and polish. Using 1,1,1-TCE, CFC-113 alternative system cleaning solvent be substituted for existing cleaning solvent against screen printing ink measured the cleaning efficiency according to gravimetric analysis method and property change of gassamer according to Image Analyzer. Also, Cleaning process system carry with excellent cleaning efficiency studied which was proposed new cleaning process including ultrasonic and vibration cleaning process be substituted for existing mixed cleaning method of dipping and polish.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.984-993
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• 2003

In Gravure printing process, there are a lot of printing errors caused by expansion and contraction of printing materials and difficulty of printing of small letters, accordingly we cannot detect those errors with eyes. In this paper, we describe the algorithm which can detect small errors automatically in Gravure printing process and a real-time detection system adopting the algorithm. We present the Perimetric Mask algorithm that can eliminate tiny errors occurring near the contour of printing objects to achieve accurate inspection, and also construct an algorithm utilizing symmetry transform which can emphasize tiny errors to make a robust inspection system. We have made a system running in real-time and verified the efficiency of the algorithm.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.11.1-11.1
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• 2009

Bulk-heterojunction type organic photovoltaic cells have been remarkably improved due to the development of efficient donors and post treatment process. However, most of researchers have studied on the OPVs using spin-coating method during the past decade. To commercialize the OPVs, much cheaper printing process should be developed such as inkjet, screen, gravure, and so on. In this study, we have focused on the development of printing technology using Inkjet and Aerosol-Jet printing, which can offer reliable device performance. Finally, 4.5% power conversion efficiency can be achieved under AM 1.5 1sun light illumination, which is the highest value in printed OPVs. We reveal that substantial improvement can be realized by highly efficient bulk heterojunction after printing. Also, we can confirm these two printing methods are promising fabrication methods for large area OPVs. Also, flexible and large area (18 cm2) printed OPVs have been fabricated and device performance will be discussed in detail.